Intravenous infusion therapy is a widespread practice when it comes to administering medication to hospitalised patients. There are different types of intravenous lines that have different clinical uses. Although, generally speaking, among peripheral intravenous lines (the catheter or canula is inserted into a vein in one of the extremities, usually in the hand or forearm) and central intravenous lines (the tip of the catheter is located in the superior vena cava in front of the right atrium in the heart), we will see that there are several types of intravenous lines within each category. The decision to use one or the other will be based on various factors:
- The type of drug to be administered. There are drugs that can be irritating or vesicants, damaging the walls of the vein through which they are administered, especially if the vein is small in size. Similarly, it is sometimes necessary to administer multiple drugs at the same time, which means higher infusion volumes.
- Treatment duration. A catheter inserted into a peripheral venous line cannot be maintained for extended periods of time.
- The age and health of the patient. Peripheral intravenous lines can be complicated to use in elderly patients or patients with vascular pathologies. Similarly, in newborns and infants the peripheral veins may not be of a sufficient size in order to properly administer the necessary medication.
- Patient comfort. In cases long-time treatments (such as chemotherapy), in which multiple punctures must be made, the patient may prefer to use a central line for a certain amount of time. When it comes to peripheral lines, it’s important to avoid patient’s mobility and facilitate their comfort to the greatest extent possible.
Peripheral intravenous lines
These are the most widely used in the emergency room, delivery room and inpatient wards. They are also the simplest, since all they require is the mere insertion of a cannula-type catheter in order to quickly start the infusion. However, the aforementioned factors must be taken into account when deciding which of these lines to use. The cannula is usually inserted into the back of the hand, forearm or antecubital fossa, but in certain cases (babies, people with any kind of problem in their upper limbs, etc.) it is possible to opt for the veins in the foot.
One disadvantage of the peripheral intravenous lines is their limited duration, which forces us to change the point of insertion from time to time, depending on the clinical staff’s judgment. In addition, the peripheral veins are of a smaller size, which limits the volume of medication that can be administered.
Central intravenous lines
Central intravenous lines are inserted into veins of a much greater size, which allows for the infusion of greater volumes while reducing the risk of extravasation. In addition, they are much more durable. It is precisely for these reasons that they are widely used in ICUs and for cancer treatments.
There are several types of central intravenous lines, each with different uses:
- Central venous lines with a simple catheter, inserted directly into a large vein (usually the jugular or subclavia)
- Intravenous reservoir , also known as “port” or “port-a-cath” (permanent or semi-permanent central venous lines). In this case, a reservoir with a silicone septum is inserted under the skin of the patient’s chest, through which the medication is injected using a non-coring needle. The biggest advantage of this type of catheter is that it is fully implanted inside the patient, thus avoiding, among other things, the complications that arise from the insertion point in the skin.
- PICCs: peripheral venous central veins, using a long catheter that reaches a thick vein. X-rays are usually used to confirm that the tip of the catheter is at the right point. This type of catheter can be implanted by means of a nursing technique, which avoids the patient having to undergo a surgical procedure, and allows properly trained nurses to autonomously manage the placement process for these types of central lines. They can have one or more lumens.
- Midlines: Similar to the PICCs but simpler to place and shorter in length. Strictly speaking, they cannot be considered to be central lines since the tip of the catheter is not located in a central vein but rather in a peripheral one, but given their greater length in comparison with a peripheral line, as well as the greater existing blood flow in the place where the drug comes in contact with the blood, they allow drugs to be infused that should not be passed through a cannula under any circumstances.
The central lines inserted into large veins or the PICCs are frequently used in the ICU, where a greater number of concomitant drugs are commonly used. These lines require a larger vein, both to infuse the appropriate volume and to minimise the risk of extravasation.
The ports reservoirs are often used in patients who need to be treated for prolonged periods of time or who require a treatment that is repeated frequently. They are widely used in cancer patients, as they avoid the need to perform frequent punctures, in addition to other types of patients who suffer from chronic pathologies and who require the administration of recurrent intravenous medication.